Numerous mechanical and electro-mechanical compliant devices have been developed in the course of the evolution of robot technology. These compliant devices, along with the software programs that sense and control the robot operations, greatly influence the overall robot performance, which is often related to the ability of the robot to acquire a work object and perform one or more simple mechanical tasks. In many robot operations, these compliant devices, to perform adequately, should exhibit non-linear, variable, and/or adjustable compliance, a plurality of degrees of freedom, provide damping, have some degree of shock and/or vibration protection, and be able to correct for variations in misalignments between the device and a mechanism to be worked on.
Among the prior art devices which serve as robot joints or end-effect connectors are manipulators used for tooling operations which exhibit compliance and some limited degree of damping where the compliance is obtained through springs which are axial with respect to the transverse direction of the tool motion. This kind of manipulator is not useful where large angular and translational motions are require. Other manipulators are rigid, linear force systems. They have no damping or shock and vibration protection capability. Still other manipulators employ wires or cables which are mounted in an axis which is parallel to the major axis of its tool and which are rigid enough to support the tool and yet give the manipulator some compliance and damping and limited self-alignment capability. This cable configuration, however, severly limits the torquing capability of the manipulator. If the supporting members are made more rigid, as they are in some devices, the device can not withstand substantial shock and vibration and will have problems with binding when its tool and the work piece are not aligned. Still other prior art devices employ spring systems to develop compliance which may be linear or non-linear and subject to a threshold. The prior art does not include a robot joint with a high level of damping, six degrees of freedom, the ability to acquire a work object with substantial side and angular misalignment between the tool and the work object, the ability to provide position feedback for alignment correction, variable and adjustable compliance, high load capability and stackability.